Tin-Based Perovskite Solar Cells Containing a Perylene Diimide Cathode Interlayer with a Copper Top Electrode

Interfacial modulation is crucial for optimizing charge carrier management and thwarting undesired ion-metal diffusion in perovskite photovoltaics. This study highlights a groundbreaking approach, employing semiconducting perylene-diimide (PDINN) as a cathode interlayer (CIL) in an inverted tin halide perovskite solar cell (THPSC). PDINN imparts the THPSCs with a remarkable efficiency rate of 13.05% as well as substantial stability, achieving the best performance among reported THPSCs thus far. The incorporation of PDINN improves the energy level alignment and mitigates the interfacial trap density, with PDINN also serving as a robust diffusion barrier to Cu and I ions due to the strong interactions between it and the PC61BM electron transport layer or the Cu cathode. The PDINN CIL introduced in this study is a pioneering application in THPSCs that concurrently boosts efficiency while also ensuring unprecedented stability.